The present invention relates generally to valves, and more specifically relates to butterfly valves which may be coupled and uncoupled without exposing the content of the valves to the outside environment.
Valves are used in material handling such as to regulate the flow of powder in conduits and in and out of containment vessels. In certain applications, it is important to isolate the material from the outside environment. For example, in chemical industries and pharamaceutical industries it may be necessary to isolate a material from the environment to maintain the purity and sterility of the material, to protect the outside environment from toxic or other harmful effects of the material, or both. However, some applications require not only regulation of flow through the valve, but also the ability to separate the conduit and/or containment vessel while maintaining the integrity of the system. This may be especially desirable where chemicals being handled are granular or in the form of a powder.
One prior device is disclosed in Soviet Inventor's Certificate No. 905,149 which shows two spring-biased elliptically shaped butterfly valves which are forced open upon coupling of two conduits. Another device is shown in Brazilian Patent No. PI 8705947A which discloses a three-stage valve used in powder transfer.
The present invention provides advantages over these prior devices while maintaining a relatively simple design which is interchangeable with corresponding valve halves, and is readily cleaned and sterilized and assembled by the operator.